Multi-break fluid-blast circuit breaker



April 27, 1965 J. B. MaCNElLL ETAL MULTI-BREAK FLUID-BLAST CIRCUITBREAKER Filed Oct. 28, 1960 4 Sheets-Sheet 1 April 27, 1965 J. B.MaCNElLL ETAL 4 Sheets-Sheet 2 IIB April 27, 1965 J. B. MacNElLL ETAL3,180,959

MULTI-BREAK FLUID-BLAST CIRCUIT BREAKER Filed Oct. 28, 1960 4Sheets-Sheet 5 April 27 1965 J. B. MaGNElLL ETAL 3,180,959

MULTI-BREAK FLUID-BLAST CIRCUIT BREAKER Filed OCt. 28, 1960 4Sheets-Sheet 4 United States Patent O 3,189,959 MULTI-'BREAK FLUlD-BLASTCRCUET BREAKER Y John B. MacNeill, Pittsburgh, Pa., and Beniainin P.Earlier, deceased, late of Monroeville, Pa., by Mellon National Bauliand Trust Company, executor, and Wayne S. Aspey, Monroeville, Pa.,assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., `acorporation of Pennsylvania Filed ct. 28, 1960, Ser. No. 65,359 9Claims. (Cl. Zilli-1457) 1This invention relates to circuit interruptersin general and, more particularly, to arc-extinguishing structurestherefor.

A general object of the present invention is to provide an improvedcircuit interruptor, particularly adapted for interrupting higi-amperage currents at hir/l1 voltages, but it will be obvious to thoseskilled in the art that certain features of the invention are applicableto low-power ratings. For purposes of illustration, the circuitinterrupter described herein is suitable for `23() kv. circuits and iscapable of interrupting 15 million kva.

In United States patent' application, filed September 13, i957, SerialNo. 683,760, now United States Patent 3,150,245, issued September' 22,1964, to Winthrop M. Leeds and Benjamin P. Baker, and assigned to theassignee of the instant application, there is illustrated and claimedcircuit-interrupting structures utilizing liqueiied gases as thearc-extinguishing mediums.

it is an additional object of the present invention to improve upon theinterrupting structures set out in the aforesaid patent application, andto render the sante suitable over a wide current' and voltage range.

A more specific object of the present invention is to provide animproved circuit interruptor in which a plurality of arc-extinguishingunits are secured to one end of a conventional-style terminal bushing,and the interrupting units extend into a porcelain-clad, or other'feather-proof casing and are adaptable for ready inspection.

Another object is to provide an improved circuit interrupter involvingone or more arc-extinguishing units in whicnimproved valve means areassociated with the movable Contact structure so as to control thejetting of a suitable arc-extinguishing liquid under pressure into theone or more arc-extinguishing units.

A further object of the present invention is to provide an improvedmounting arrangement for multiple-unit-type circuit interrupters inwhich one or more tie-rods, under tension, are associated with springmeans to retain a surrounding weather-proof casing under compression.Preferably, suitable means are additionally provided to enable a rapidinspection and replacement of parts of the interrupter, if needed,following long operational life of the interruptor.

Yet a further object of the present invention is to provide an improvedvalve means which will insure a feeding, or jetting oi arc-extinguishingliquid into one or more arc-extinguishing units only during the openingoperation, while retaining the said valve means closed during theclosing operation.

Further objects and advantages will readily become apparent upon readingthe following speciication, talren in conjunction with the drawings, inwhich:

FIGURE 1 is a side elevational View, partially in ljaented Apr. 27, 196

section, of a circuit interrupter embodying the present invention;

FG. 2 is a fragmentary vertical sectional vieuI taken through the lowerend of the arc-extinguishing assemblage of ENSURE l, the contactstructure being illustrated in closed-circuit position;

3A and 3B collectively illustrate, in enlarged fashion, verticalsectional View taken through the lower end of the arc-extinguishingassemblage, substantially along the line lll-lll of FIG. 4, one of thethree seriallyarranged arc-extinguishing units being omitted forpurposes oi clarity, and the contact structure being shown in theclosed-circuit position;

FlG. 4 is a sectional view taken along the line IV-lV oi FIG. 3B lookingin the direction of the arrows;

FlG. 5 is a fragmentary sectional view taken along tbe line V-V ot FlG.3A, looking in the direction of the arrows;

FlG. 6 is a fragmentary sectional View taken along the line fi-Vl ofFIG. 4 looking in the direction oi the arrows;

FiG. 7 is a fragmentary sectional view taken along the of i lG. 4looking in the direction of the arrows, the several operative partsbeing shown in the closed-circuit position; and,

FIG. S is a fragmentary vertical sectional view take along the lineVlllkVlll of FlG. 4 at the lower end of the interruptimT assemblage toillustrate the compressionspring arrangement'.

Referring to the drawings, and more particularly to FiG. l thereof, thereference numeral l generally designatos a circuit interruptercomprising a rather conventional-type terminal bushing 2 supportedwithin a mechanism housing 3 and having the lower end 4 (FlG. 3A)thereof extending downwardly interiorly within a casing structure,generally designated by the reference numeral 5 in FIG. 1.

The casing structure 5 includes a pair of porcelain, or otherWeather-prooi casings 6, 7 secured together in end-to-end arrangement asshown. A cap structure 8 is secured to the lower end of porcelain casing7, as shown in FIGS. l and 8.

The mechanism housing 3 is of generally cylindrical configuration, andhas an outwardly extending grounded ilange ring iii, which is supportedby a grounded metallic traine-work comprising angle-irons ll, whichextend in a horizontal direction, as shown in FIG. 1. The angleironhorizontally-extending frame-work 11, is, in turn, supported an adequatedistance up in tne air by verticallyextending angle-irons l2, i3,supported on a suitable base liand are diagonally interbraced bydiagonallyextending angle-irons l5. The inter-braced verticallyextendingstructural members l2, .i3 rigidly secure the mechanism housing 3rlxedly in a proper position and, in the particular embodiment of theinvention illustrated in FIG. 1, support the upper end ot the terminalbushing 2 vertically. However, it will be apparent that the circuitinterruptor l, instead of being supported vertically, as s iown, couldbe supported generally horizontally or in any other desired position.

Surrounding the terminal bushing 2 and also disposed below the mechanismhousing 3 is a pair of current transters le, i7, which, may be arranged,if desired, for relay protection, as described and claimed in UnitedStates patent application filed March 31, 1958, Serial No. 725,230, nowUnited States Patent 3,032,689,

oneness issued May 1, 1962, to B. F. Baker and R. F. Karlicek Vandassigned to the assignee of the instant application.

With reference to FIG. 2, it will be noted that secured to the lowerinternal end 4 of the terminal bushing 2 is a plurality, in thisparticular instance three, arc-extinguishing units I8 collectivelycomprising an arc-extinguishing assemblage, generally designated by thereference numeral 2?, fand, as shown, disposed interiorly within thecasing structure S. Thethree arc-extinguishing units 1% are adapted tobe :simultaneously actuated to the open and closed-circuit positions bya pair of insulating operating rods 21, only one of which is shown inFIG. 2. Reference may be had to FIG. 3A for a showing of the secondoperating rod 21. With reference to FIG. 3A, it will be observed thatthe upper ends of the insulating operating rods 21 are pivotallysecured, by pins 22, to crank-arms 23, the latter being aflixed to arotatable crank-shaft 24,'

journaled in bearings 25 extending interiorly of the mechanism hou-sing3.

With reference to FIG. 5, it will be observed that rotation of thecrank-shaft 24 is effected by means of a crankarm 26, pivotallyconnected by a pin 27 to a link 28. The right-hand end of the link 28 ispivotally connected, by a pin 30, to a bifurcated crank-arm 3i, aliixedto a vertically extending crank-shaft 32, which extends through agas-tight seal 33 externally of the mechanism housing 3.

With reference to FIGS. l and 5, it will be noted that the lowerexternal end 34 of the crank-shaft 32 is keyed to a crank-arm 55. Thefree end of crank-arm 35 is pivotally connected to a link 36 (FIG. 1),which is pivotally connected, as at 37, to a bell-crank 38, the latterbeing pivotally mounted upon the horizontal framework Il. To the outerend of one arm 4@ of bell-crank 38 is pivotally connected, as at 4l, anupwardly-extending insulating operating rod d2, the lower end of whichmay be connected to any suitable driving mechanism, not shown.

Thus, downward movement of operating rod 42 will effect rotation of thebell-crank 3S in a counter-clockwise direction to effect therebyrotation of crankshaft 32 and upward opening movement of the pair ofinsulating operating rods 2li interiorly of the upper porcelain casing6.

As mentioned, the two insulating operating rods 2l effect simultaneousopening and closing movement-s of the movable contact structure 43. Withreference to FIG. 3B, it will be observed that the lower end 44 ofinsulating operating rod 21 is pivotally connected, as at 39, to areciprocally movable bracket 45, the lower end of which is secured tothe upper movable contact 46 by a pair of machine screws 47. The bracket45 has an encircling annular portion 48, to which is integrally formed,but not shown in FIG. 3B, a second upstanding bracket 45, which issecured to the second operating rod 23. in the saine manner that thebracket portion 45 is secured to the first mentioned operating rod 2l,as shown in FIGS. 2 and 3B.

As shown in FIGS. 3B and 4, two insulating operating rods Si)mechanically interconnect the several movable contacts 46 forsimultaneous movement. A bracket 5I, somewhat similar to the bracket 45,is secured to the operating rod Sti at one end, and has its other lowerend secured by screws 47 to the lower-most movable contact 46, as shownin FIG. 3B. Actually, there are three interrupting units I comprisingthe arc-extinguishing assemblage 20, but FIG. 3B only shows the upperand lowermost arc-extinguishing units IS, the middle unit ll beingomitted for purposes of clarity. Y Y

Cooperating with each movable Contact 4d is a relatively stationarycontact structure, generally designated by the` reference numeral 52,and including stationary resilient finger contacts 53. As shownV in FIG.3B, the finger contacts 53 resiliently engage the lower ends of themovable contacts 46. In addition, an arcing Contact stud 54 projectsinteriorly of each hollow movable tubular contact 46 in theclosed-circuit position, as shown in FIG. 3B. The arcing contact stud 52has a tapped bore 5:5 provided at its lower end to accommodate a machinebolt 56, which rigidly secures the arcing Contact stud 52 to a contactsupport 57. It will be noted that the contact fingers 53 are formed byslotting the upper tubul ar portion of the contact support 57. The lowerend of the contact support 57 likewise forms resilient nger contacts 58,which bear upon the upper sides of the movable contacts 46.

The lseveral contact supports 57 are maintained in fixed spaced relationrelative to each other by three tie-rod supports oil, more clearly shownin FIGS. 2 and 4. As shown in FIG. 2, the three insulating tie-rods o@have reduced portions 6l thereon, which secureV support sleeves 62 inspaced fixed relation. As shown in FIG. 3B, the support sleeves havethreaded support holes 63 provided therein, into which are threadedlysecured thecontact supports 57. The support sleeves 62 haveoutwardly-jutting apertured bracket portions 64, which assist in guidingthe longitudinal reciprocal motion of the two insulating operating rodsEil and hence the movable contacts 46.

As illustrated in FIGS. 2 and 3B, one of the insulating operating rods5@ is effective to bring about opening and closing movement of theseveral movable contacts 46 by virtue of the bracket portions 45, 5l.The companion operating rod Sti, as shown more clearly in FIGS. 4 and 7,has secured thereto a plurality of spaced cams 65 having beveled ends66, 67. Besides carrying the three cams 65,

the companion operating rod 5d is likewise secured to a bracket 5I, notshown, secured to the annular portion 48. It will be remembered thatFIGS. 3A and 3B are a somewhat quarter-section view, as taken along theline III-III of FIG. 4; consequently, only one insulating operating rod5t? is shown, and reference must be had to FIG. 4 for a showing or thecompanion operating rod 50, which carries the three spaced cams 65, thepurpose for which will be described hereinafter.

With reference to FIG. 3B, it will be observed that secured to the upperside 68 yof each contact support 62k is an insulating orifice structure,generally designated by the reference numeral 70. The orice structure7tl includes an insulating orifice sleeve member 7l having a restrictedorifice opening 72. Viewing the lower orifice structure 7th of FIG. 3B,it will be noted that immediately below the restricted orifice opening72 is a plurality of,

. in this particular instance sixteen, jet apertures 73, which directliquid under pressure radially inwardly into the arc region to effectimmediate extinction of the arc, not shown, drawn between each movableContact 46 and each stationary contact 52.

Surrounding the insulating orifice structure 70 is a metallic feedingmanifold structure 74, which serves to supply liquid, under pressure,into each of the Vsixteen jet apertures '73. The supply manifoldstructure 74 is connected to a valve means 75, comprising a ball valve76, which is spring-biased closed over an inlet opening 77 by acompression spring 7d. The lower end of the compression spring 78 seatsupon a spring seat 8), which is supported from the contact support 62;.

An insulating liquid supply tube 81, shown more clearly in FIGS. 4 and6, connects to all three valve means 75. Asshown in FIG. 6, the liquidsupply tube 81 comprises a plurality of tube sections 82, which feedinto an inlet passage 83 associated with each of the valve means 7S.Normally, in the open and closed-circuit positions of the interrupter 1,the ball valve 76 is maintained closed over the inlet opening by thebiasing action exerted by the compression spring '78. It is desired toeiect opening of the ball valves 76 by relaxing the spring pressure onlyduring the opening operation of the circuit interrupter 1. During theclosing stroke of the interrupter, it is desired to maintain the ballvalve 76 closed upon its valve seat 84. To effect this end, acollapsible valve-operating lever, generally designated by the referencenumeral85 in FIG. 7, is employed. The valve operating lever 85 ispivotally mounted, by a pivot pin 86, to a valve support S7, whichconstitutes an'integral part of the valve casing 88. The valve operatinglever 85 has a spring compressing arm adsense 85a, which effects aslight compression of the compression spring 7S, the latter tending tomaintain the ball valve 76 in its closed position over inlet opening 77.In addition, the valve-operating lever 35 has a second valveactuatingportion 8511, to which is pivotally connected, by a pivot pin 89, abifurcated cam lever 99. The cam lever 90, as shown in FIG. 7, has anintegral web, or bight portion 90a, which is biased by a torsion spring91 into abutting engagement with an outer extremity, or stop 92 ofthevalve actuating arm @b.

With reference to FIG. 7, it will be apparent that up ward openingmotion of the insulating operating rod Eil will carry upwardly therewiththe cani 65. The upper beveled end 66 of cam 65 will engage a earnroller 93 pivotally mounted upon a pin 94 to the outer end of the camlever 9i). In the opening, or upward motion of the operating rod Sti,the cam 65 will force the web portion 90a of cam lever 9b againstabutment $2 of valve-operating lever 85 to effect compression of thecompression spring '78. This will permit liquid under pressure containedwithin supply tube 81 to pass through inlet passage S3 over valve seat84, past ball valve 76 and into the manifold supply structure 74 to jetliquid under pressure through the sixteen liquid jet passages 73 andinto the established arc.

During the closing operation of the circuit interruptor 1, that is,during downward motion of the operating rod 5t), with reference to FIG.7, the beveled end 67 of cam will strike cam roller 93, and willcollapse the cam lever Qtlin a clockwise direction about pivot pin 89 inopposition to the biasing action exerted by torsion spring 91. This willrender the valve operating lever inactive during the closing operationof the interrupter as far as compressing spring 73 is concerned. Fromthe foregoing, it will be apparent that only during the openingoperation is liquid jetted through the jet orifices 73 to effect arcextinction. During` the closing operation, the valve structure 75remains closed.

With reference to FIGS. 2, 3A and 3B, it will be noted that theporcelain casings 6, 7 have cemented to their opposite endsmounting-harige rings 95, 96, 97 and 98, as by cement 101i. .The capstructure 8, disposed at the lower end of the circuit interrupter 1,includes a cupshaped metallic closure cap 101 having a peripheral flangeportion 102, which is secured by bolts 103 to a support plate 104. Themounting-flange ring 9S, disposed at the lower end of the porcelaincasing '7, is secured, by bolts 10S, to the support plate 104. f

With reference to FIG. 3B, it will be observed with the contact-mountingSleeve 62a, associated with the lowermost arc-extinguishing unit 18, hasa lower sleevelilte depending portion 62b, which is exteriorly threaded,as at 106. Threadedly secured to the support sleeve 62a is a clampingnut 1117, which has an outer flange portion 198, which bears against anannular apertured spring plate 111D. The apertured spring plate has aplurality of apertures 111 (FIG. 8), through which extend spring bolts112, the upper ends 113 of which are threadedly secured in tappedapertures 114.

Encircling the spring bolts 112, and disposed between the annular springplate 110 and the support plate 104, are a plurality ofstrongcompression springs 11S, which exert compressive stress upon theporcelain casings 6, 7 and correspondingly exert tension upon thetie-rod supports 60. Y

Since the upper ends 116 (FIG. 2) of the tie-rod supports 60 are fixedlysecured to laterally jutting brackets 117, integrally formed with aclamping casting 1153 threaded to the lower end 4 of the bushing 2, itwill consequently be observed that the terminal stud, not shown, passinginteriorly through the terminal bushing 2, together with the tie-rods 60are all in tension and not only exert compression upon the casings 6, 7,but also exert compression upon the external porcelain casing 119associated with the upper end of the terminal bushing 2.

With reference to FIG. 3B, it will be noted that the support plate 1Mhas cut-out portions 104:1 to accommodate longitudinal reciprocatingopening and closing motion of the two insulating operating rods 50.

As shown in FIG. l, a liquid storage reservoir 12) is provided, which ispreferably at least partially filled with a liquid under pressure. Thisliquid could be oil, or any suitable arc-extinguishing liquid underpressure, but preferably it is desired to utilize a liquefied gas, suchas liquefied sulfur hexafluoride (SFG) gas under a pressure of say 10G()p.s.i. As shown, a supply pipe 121 leads through the mechanism housing 3(FIG. 3A) and downwardly interiorly within the upper porcelain casing 6,connecting with the lower supply tube $1, which feeds the several inletpassages 83. Following the jetting of the liqueiied (SFS), or otherliquid, into the several arcing regions 122, the liquefield SFS gasexpands into its gaseous phase, and exhausts into the interior region123 interiorly of the casing 6, '7. This region 123 may be at severalatmospheres pressure, in the case of sulfur hexaiiuoride gas, to insureadequate dielectric strength in the open-circuit position of the contactstructure. This exhaust SFS gas is collected by a collecting pipe 12,4(FIG. 3A) and is drawn downwardly through a pipe 125 (FIG. l) into acompressor 126, where it is liquefied and forced, in liquid form,upwardly through a feed pipe 127 back to the liquid reservoir 126.

A distinct advantage of the circuit interrupter construction illustratedin FIG. l is the ease of inspection and replacement of worn parts. Forexample, following exhausting of the SFS gas from the interior of thecircuit interrupter 1, the lower closure cap 101 may be removed byunscrewing the bolts 1133. This will cause a contact stud portion 12S tobe retracted from spring lingers S8 associated with the lower contactsupport 57. Following removal of the cap 161, the clamping nut 1t?? isbacked off of the support sleeve 62a to release the compressive forceexerted by the several compression springs 115.

kThe clamping nut 1117 is removed, and bolts 130 (FIG.

3B) are removed to permit dropping of the lower-most porcelain casing 7downwardly from the circuit interrupter 1, exposing the several spacedserially related arcextinguishing units 18 for inspection. Theinterruptor 1 may then be operated to the open and closed-circuitpositions, noting the condition of the contacting parts. With the units13 exposed, any worn parts may readily be replaced. The lower casing 7may then be secured, by the bolts 130, to the flange ring 97 (FIG. 3B),and the clamping nut 1137 screwed over the threads 196 to compress thespring plate 119, thereby causing compressive force to be exerted alongthe casings 119, 6 and 7. Finally, the lower closure cap 1G11 may be putback into place with the stud portion 12S engaged by the lower-mostcontact fingers 5S and with the bolts 163 secured into place.

The opening operation of the circuit interruptor 1 will now bedescribed. In the closed-circuit position of the interrupter 1, thecircuit obviously extends from the upper terminal 131 through theterminal stud, not shown, exteriorly through the terminal bushing 2, tothe lower clamping casting 118 threadedly secured to the lower end ofthe terminal stud. The circuit then extends through a dependent slottedcontact-sleeve portion 132 to the upper-most movable contact 46. Thecircuit then extends through the lingers 53 of upper fixed contactsupport 57, through the lower lingers 58 of said contact support 57 tothe middle movable contact 46. The circuit continues in similar fashiondown through the fingers 5S, associated with the lower-most contactsupport 57, and to the terminal stud 128 of removable closure cap 161.The circuit continues by way of the lower stud portion 133 to the othertransmission line L2.

To effect an opening operation of the interrupter 1, the insulatingoperating rod L12 (FIG. l) is pulled downwardly by any suitableoperating mechanism, not shown. This will effect, through the linkagepreviously described,

' arcing zone.

upward opening movement of the insulating operating rods 21, and upwardcorresponding 'opening movement of the two insulating contact operatingrods 50. Prior to contact disengagement, the cams 65, associated withthe right-hand contact rod t) (FIG. 4), engage the several cam rollers93 to eiieet counter-clockwise rotative motion of the several valveoperating levers 35. The spring seat engaging portions 85e of the valvelevers 8S compress the-compression springs 78 to permit the liquidpressure to force the ball valves 76 downwardly, `thereby permitting`liquefied sulfur hexafluoride (SFS) gas to pass by the ball valves 76,through the supply manifold passages 74 and through the several jets 73of the units 1S into the arcing regions 122. This preferably occursprior to contact disengagement.

Continued upward opening movement of the contact rods 50 causes contactdisengagement between contacts 46, 5S, Vso that an arc, not shown, isdrawn through each restricted orifice 72 associated with eacharc-extinguishing unit iti. The inwardly jetting streams of liquefiedsulfur hexafluoride (SP6) gas, directed into the several arcs quicklyeffects the extinction thereof, and continued opening motion of thecontact 'operating rods Si? causes the cams 65 to slide off, ordisengage the cam rollers 93, thereby permitting the compression springs78 to effect reclosure Aof the Vseveral ball valves 76. This stops thejetting action, and the contact structure separates to kan Visolatedopen-circuit position. Y

To effect reclosure of the contact structures and thereby effect closingof the circuit interrupter l, the external operating rod 42 (FIG. l) ismoved upwardly. Through the linkage, previously described, this effectsdownward closing motion of the pair of insulating operating rods 2i,thereby eiiecting corresponding downward closing motion of the twocontact operating rods 5. When the beveled ends 67 of the several cams65 strike the rollers 93, the cam levers 9@ rotate in aclockwisedirection about pins 89, against the biasing action exerted bytorsion springs 9i, and the valve levers 85 remain stationary andVinoperative during such a closing operation. The contact rods 5i) effectcontact reclosure between contacts 46, 5?, and the circuit is completedthrough the circuit inter- Arupter ll.

From the foregoing description, it will be apparent that there isdescribed a novel circuit interrupter 1 readily adaptable for differentvoltage and current ratings by utilizing 'one or more elementalarc-extinguishing units 113 in series. It will be observed that all ofthe extinguishing units 18 are dependent from the lower end 4 of theterminal bushing 2 in the preferred mounting arrangement, and arereadily observed for inspection purposes by dropping the lower-mostporcelain casing 7, as previously described. The liquefied sulfurhexafluoride (SP6) gas is jetted into the arcing regions 122 prior toarc drawal although the time of feeding, or supply may obviously bevaried depending upon the application requirements. The valve means 75is so arranged as to `open only during the opening operation.

From the foregoing description of the invention, it will be apparentthat there is disclosed a novel type of circuit interrupter utilizingliqueiied gas injected into the Although liquefied sulfur hexafluoride(SFS) gas has been described as an example of a possible liqueed gas, indescribing the structure, it is to be clearly understood that liqueedselenium hexafiuoride (SeF), or any 'one or a mixture of two or more ofthe liquefied gases enumerated above and below may be employed insubstitution of liquid sulfur hexafluoride (SFS) gas.

The various gases, which are suitable for use in interrupters of thetype considered, have similar properties and characteristics are set outin the following table.

Vapor Dielectric Boiling Pressure, Strength Point ,It/sq. in with Air CGauge at or Ng -78 830 0.9 -10 35 2. 0V 63. 8 300 2. 2 34. 5 2. D -30160 2. 5 -28 68 2. 4 ,47.,5 139 3.0 -78 1.8 -37 2. 0 -8l. 5 325 1.4CFaBr -58 195 l. 25

Although the foregoing liqueiied gases may be used to advantage,exceptional and unusual performance is obtained with liquid SP6 andliquid Sel-76, since the gaseous phases of these two materials are sohighly effective in arc interruption and high dielectric insulation.

In addition, conventional arc-extinguishing liquids under pressure, suchas oil, carbon tetrachloride, etc. may be employed with advantage.

Although there has been shown and described a specic circuitinterrupting structure, it is to be clearly understood that the same wasmerely for the purpose of illustration, and that changes andmodifications may readily be made therein by those skilled in the artwithout departing from the spirit and scope ofthe invention.

We claim as our invention:

l. A multi-break circuit interrupter including a Vterminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line terminal means disposed at one end of saidterminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingwithin one end of said insulating casing means, the external end of saidterminal bushing having an insulating casing, second line terminal meansdisposed adjacent the other end of said casing means, the terminalbushing and the casing means being in substantial yalignment, amulti-break arc-extinguishing assemblage supported by said other end ofthe terminal bushing and positioned between said other end of theterminal bushing and said second line terminal means within theinsulating casing means, the arc-extinguishing assemblage including aplurality of liquid-jet are extinguishing units, valve means associatedwith each unit, liquid supply means for supplying liquid under pressureto each valve means, an oriiice structure through which the arc in eachunit is drawn and having a plurality of radially disposed jet passages,a movable contact cooperable with a relatively stationary contact withineach unit to establish an arc through the orifice structure of the unit,and a plurality of insulating tie rods terminating Iat said other end ofthe terminal bushing and supporting said arc extinguishing units infixed spaced relation and additionally maintaining said insulatingcasing means and said casing in compression.

2. A multi-break circuit interruptor including a terminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line terminal means disposed at one end of saidterminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingwithin one end of said insulating casing means, second line terminalmeans including a terminal cap and a spring plate disposedl adjacent theother end of said casing means, the terminal bushing and the casingmeans being in substantial alignment, a multi-break arcextinguishingassemblage supported by-one or more tie rods at said other end of theterminal bushing and positioned between said other end of the'terminalbushing and said second line terminal means within the insulating casingmeans, the arc extinguishing assemblage including a plurality ofliquid-jet are extinguishing units, valve means associated with eachunit, liquid supply means for supplying liquid under pressure to eachvalve means, an orifice structure through which the arc in each unit isdrawn and having a plurality of radially disposed jet passages, amovable contact cooperable with a relatively stationary contact Withineach unit to establish an 'arc through the orifice structure of theunit, said one or more insulating tie rods supporting saidarc-extinguishing units in fixed spaced relation and maintaining saidinsulating casing means in compression by means of said spring plate,one or more compression springs disposed within said terminal cap `andbearing against the spring plate and said casing means, and a clampingnut mounted upon the assemblage adjacent said second line terminal meansfor increasing pressure upon the spring plate.

3. A multi-break circuit interrupter including a terminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line terminal means disposed at one end of said'terminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingwithin one end of said insulating casing means, second line terminalmeans disposed adjacent the other end of said casing means, the externalend of the terminal bushing having a weatherproof insulating shell, theterminal bushing and the casing means being in substantial alignment, amulti-break arc-extinguishing assemblage supported by said other end ofthe terminal bushing and positioned between said other end of theterminal bushing and said second line terminal means within theinsulating casing means, the arc-extinguishing assemblage including aplurality of arc-extinguishing units, separable contact means associatedwith each Vunit to establish an arc within the unit, and a plurality ofinsulating tie rods secured to said other end of the terminal bushingand supporting said arc-extinguishing units in fixed spaced relation andmaintaining said insulating casing means and external insulating shellin compression.

4. A multi-break circuit interrupter including a terminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line terminal means disposed at one end of saidterminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingwithin one end of said insulating casing means, second line terminalmeans disposed adjacent the other end of said casing means, the terminalbushing and the casing means being in substantial alignment, amultibreak arc-extinguishing assemblage supported by said other end ofthe terminal bushing and positioned between said other end of theterminal bushing and said second line terminal means Within theinsulating casing means, the arc-extinguishing assemblage including aplurality of arc-extinguishing units, separable contact means associatedwith each unit to establish an arc within the unit, a terminal capassociated with said second line terminal means and having a pluralityof compression springs therein, a spring plate, said compression springsexerting compressive force upon ther insulating casing means and againstthe spring plate, and clamping means secured to the arc-extinguishingassemblage and forcing the spring plate to compress the springs, wherebythe casing means will be subjected to compressive force whereas thearcextinguishing assemblage will be subjected to tensile stress.

5. An arc-extinguishing assemblage including a plurality ofserially-related arc-extinguishing units, each unit including agenerally tubularly-shaped contact support having a stationary contactadjustably threadedly supported adjacent one end thereof, the other endof the tubularly-shaped contact support lixedly securing an insulatingorifice structure into operative position, each stationary contacthaving opposed contact fingers and an arcing rod secured to a mid-webportion thereof, and a plurality of laterally-supported tubular movablecontacts making separable contacting engagement with one set of contactfingers of one relatively stationary contact and i@ also constantcontacting engagement with the next adjacent relatively stationarycontact.

6. A multi-break circuit interrupter including a terminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line-terminal means disposed at one end of saidterminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingWithin one end of said insulating casing means, second line terminalmeans disposed adjacent the other end of said casing means, the terminalbushing and the casing means being in substantial alignment, amulti-break arc-extinguishing assemblage supported by said other end ofthe terminal bushing and positioned between said other end of theterminal bushing and said second line terminal means within theinsulating casing means, said arc-extinguishing assemblage including aplurality of serially-related arc-extinguishing units, each unitincluding a generally tubularly-shaped contact support having astationary contact adjustably threadedly supported adjacent one endthereof, the other end of the tubularly-shaped contact support fixedlysecuring an insulating orifice structure into operative position, eachstationary contact having opposed contact fingers and an arcing rodsecured to a mid-Web portion thereof, and a plurality oflaterally-supported tubular movable contacts making separable contactingengagement With one set of contact fingers of one relatively stationarycontact and also constant contacting engagement with the next adjacentrelatively stationary contact.

7. The combination 4according to claim 6, wherein a removable closurecap is associated with the second lineterminal means and has aterminal-stud portion which ma tes contacting engagement with the set ofcontact fingers of the relatively stationary contact most remote fnomsaid other end of said terminal bushing.

8. A multi-break circuit interrupter including a terminal bushing,grounded supporting means for supporting said terminal bushing adjacentthe mid-portion thereof, line-terminal means disposed at one end of saidterminal bushing, insulating casing means disposed at the other end ofsaid terminal bushing, the other end of the terminal bushing extendingWithin one end of said insulating casing means, second line-terminalmeans disposed adjacent the other end of said casing means, the terminalbushing and the casing means being in substantial alignment, amultibreak arc-extinguishing assemblage supported by said other end ofthe terminal bushing and positioned between said other end of theterminal bushing and said second line-terminal means within theinsulating casing means, the arc-extinguishing assemblage including aplurality of serially-related liquid-jet arc-extinguishing units, eachunit including a generally tubularly-shaped contact support having astationary contact adjustably threadedly supported adjacent one endthereof, the other end of the tubularly-shaped contact support lixedlysecuring an insulating orifice structure into operative position, eachstationary contact having opposed contact fingers and an arcing rodsecured to a mid-Web portion thereof, a plurality of laterally-supportedtubular movable contacts making separable contacting engagement with oneset of contact lingers of one relatively stationary contact and alsoconstant contacting engagement With the next adjacent relativelystationary contact, valve means associated with each unit, liquid-supplymeans for supplying liquid under pressure to each valve means, and meansmovable with the movable contact structure for actuating said valvemeans to the open position for supplying a quantity of liquid into eachunit during the opening operation for arc-extinguishing purposes.

9. The combination according to claim 8, wherein the orifice structureof each unit has a plurality of radiallydisposed jet passages and asupply-and-manifold passage communicating with the radially-disposed jetpassages.

(References on following page) 3,180,959 il Y Z Reieuces Cited by the`Elfmlmiiner FOREGN PATENTS. UNITED STATES PATENTS 662,215 7/ 38Germany. K 597,150 1/9-8 Knudsen 20o-148 502,443 3/39 Great Britain-1,071,s29 9/13 Turner 20o-148 5 1219923 10/59 Ffan Y n 2,667,556 1/54Van Sickle et al. 20-145 I. l 2,866,045 12/58 Leeds 200 145 BERNARD A.GLHEANY, Pllmmy Exammel. 2,979,591 4/ 61 Friedrich 200-145 MAXL. LEVY,Examiner.

3,033,962 5/62 Friedrich et al. 20D-148

5. AN ARC-EXTINGUISHING ASSEMBLAGE INCLUDING A PLURALITY OFSERIALLY-RELATED ARC-EXTINGUISHING UNITS, EACH UNIT INCLUDING AGENERALLY TUBULARLY-SHAPED CONTACT SUPPORT HAVING A STATIONARY CONTACTADJUSTABLY THREADEDLY SUPPORTED ADJACENT ONE END THEREOF, THE OTHER ENDOF THE TUBULARLY-SHAPED CONTACT SUPPORT FIXEDLY SECURING AN INSULATINGORIFICE STRUCTURE INTO OPERATIVE POSITION, EACH STATIONARY CONTACTHAVING OPPOSED CONTACT FINGERS AND AN ARCING ROD SECURED TO A MID-WEBPORTION THEREOF, AND A PLURALITY OF LATERALLY-SUPPORTED TUBULAR MOVABLECONTACTS MAKING SEPARABLE CONTACTING ENGAGEMENT WITH ONE SET OF CONTACTFINGERS OF ONE RELATIVELY STATIONARY CONTACT AND ALSO CONSTANTCONTACTING ENGAGEMENT WITH THE NEXT ADJACENT RELATIVELY STATIONARYCONTACT.